The present invention relates to a new and distinct cultivar of Tiarella and given the cultivar name of ‘Mystic Mist’. Tiarella is in the family Saxifragaceae. The new cultivar originated from a planned breeding program to create a vigorous variegated Tiarella using Tiarella wherryi ‘Heronswood Mist’ (an unpatented plant), as the seed parent, and a mass of selected proprietary Tiarella hybrids, as the pollen parents. Offspring were selected and line crossed and the most attractive vigorous and variegated plants were grown out for evaluation. Tiarella ‘Mystic Mist’ was selected as superior.